Significant progress could be made on artificial sun technology by 2023 – and it could be used to generate clean energy for China in 50 to 60 years, a senior government nuclear scientist says.
Song Yuntao, a lead scientist on the country's largest fusion energy project, told the official Science and Technology Daily on Thursday that they expected to double the burn time of man-made sun every 16 to 17 months.
Earlier this month, scientists on the project kept extremely hot plasma at a temperature three times that of the sun's core for more than 100 seconds during an experiment at their Hefei research facility. It was almost double the record set by the team last year.
They're aiming to sustain the burn for more than 1,000 seconds – using a ring-shaped device known as a tokamak – at which point the scientists expect the plasma to produce a self-sustainable nuclear chain reaction, an important step for power generation.
That milestone would be less than six years away, based on Song's estimate. "We hope to go into business in 50 to 60 years," he told the newspaper.
At the Experimental Advanced Superconducting Tokamak facility in Anhui province, the chain reaction that takes place in the sun to provide life-giving energy is simulated using plasma – two hydrogen atoms merge into one helium and in the process release a large amount of energy. This extremely hot gas – whose temperature can reach up to 10 times that of the sun's core – is contained by a strong magnetic field to prevent it from coming into direct contact with the inner wall of the reaction chamber. The tokamak fusion device was invented by Soviet physicists in the 1950s.
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The development of fusion technology – particularly the idea of applying it to nuclear reactors to generate clean energy – has been held back by the difficulty of containing the reaction so that heat is released in a slow and controllable way.
But Song said the Chinese scientists were a step ahead, in part because they could mass-produce some of the world's most advanced superconducting wires that can create a strong magnetic field using a lot less power than others.
Hundreds of tonnes of these wires – which are as fine as hair – are rolled out in Chinese factories every year at a cost of 30,000 yuan (US$4,400) per individual wire.
He said the country could start building "within a few years" a large-scale fusion plant to assess whether it was feasible to generate power.
China is a key contributor to the International Thermonuclear Experimental Reactor, or ITER, the world's largest fusion reactor which is being built in southern France. But delays and budget blow-outs mean its first experiment is not expected until at least 2025.
Song said a Chinese test reactor would make "daring innovations" and learn lessons from the ITER. Chinese media reports have previously said construction of the China Fusion Engineering Test Reactor would start in 2020 and it would be fired up to generate electricity six years later.
But Liu Yuxin, a professor of nuclear physics with Peking University, said he doubted whether the first fusion power plant could be up and running within half a century.
"The science and technology might be advancing fast, but fusion is not a pure scientific or technological problem," he said, adding that many other factors – such as unexpected changes in global politics and the world economy – could hinder progress. The Fukushima Daiichi nuclear disaster in Japan, for instance, triggered by an earthquake and tsunami, was a major setback for the industry's development.
Liu said fusion power would be worth waiting for because it was an ultimate solution to the world's energy needs. "Solar power is limited, wind unstable, hydropower over-exploited, and uranium ore will eventually be depleted," Liu said. "Hydrogen is the water that fills the oceans. It is an inexhaustible energy source."